Piston



Nov. 27, 1923. 1,475,773

R. ALLEN PISTON Original Filed Play 26 .A 1920 3 Sheets-Sheet l mgl. 1,2. e 0 C! /e 2 n." "i 5 a l I L f/ 52 I 2 5 i 6 c 2 Q 6l Z2 al @JV-ea.

Nov.- 27, 1923. 1,475g773 R. ALLEN PISTON Original Filed May 26 1920 `3 Sheets-Sheet 2 jzyefz 2074 7202er? Zien A R. ALLEN -PI'sToN Nav. v27, 1923. 1,475,773

Original Filed May 26 1920 3 Sheets-Sheet 5 P19714 IWL/1 Fz'gll. Figli:

m75 C' C f Yea Patented Nev. 27, i923.

TED STATES PATENT FFE.

.PISTON Application led May 26, 1920, Serial No. 384,495. Renewed .Tune 26, 1923.

To all whom 'it may concern:

Be it known that l, Roinnrr Amref, of Chiltern Rise. `Woodcote, Reading, in the county of Berkshire, England, a subject of the King of Great Britain and Ireland (whose post-office address is Chiltern Rise, lioodcote, Reading, .in the county of Berkshire, England), have invented certain new and useful Improvements in Pistons, of

which the following is a specification.

The type of piston packing to which my invention is applicable comprises a packing ring having one or more joints each closed by a sliding plug (hereinafter referred to as the sealing member) associated with a'wedge or choke piece (hereinafter referred to as the expandingmember) and one object of the invention is to permit yof or promote the free radial sliding of the sealing member independently of the expanding member in order to render the sealing effective notwithstanding variations in the cylinder diameter.

Another object of the invention is to provide a novel construction in which the eX- panding member,` the sealing member, and the operating springs for both members,` are all connected to forni a single unit for ease in commercial handling before installation without danger of any part becoming lost.

In the accompanying drawings:

Figure 'l to Figure 3 are sectional elevations at right angles and plan respectively illustrating a portion of a piston with packing ring joint sealing and expanding members constructed according to this invention.

Figures 4 to 6 are similar views to Figures l to 3 showing a modified form of construction.`

Figures 7 to l0 are detail views of a sleeve employed for connecting the springs shown in Figures 4t to 6.

Figures 11 to 13 are detail views of an expanding member.

Figures la to 16 are detail views of a sealing member for use with the same.

Figures 17 to 20 are detail views of suitable springs for expanding the two members.

Figures 21 and 22 are similar views to Figures l and 2 illustrating the assembling of similar details to those shown in Figures ll to 20. p

As shown in Figures l to 3 the sealing member a which is iitted in a radial bore in the body of the piston consists of a tube er sleeve slotted to receive the expanding member or choke b and leaving segments c at the outer end which extend radially across the joint (Z in the piston ring or rings e. The sealing member a is forced outwards by an involute spiral spring a and the expanding member b is forced outwards by an independent helical spring b Spring Zi is attached to the stem 62 of the expanding member b by causing the first convolution of the spring to grip in a groove or undercut portieri of the stem, whilst the spring a lis shaped to grip the opposite end coil of the spring b and also to engage by means of a iiange a2 with an annular groove or notch in the inner end of the sealing member.

By connecting the parts as described they can remain assembled while in stores or when dismantling for examination and there is no likelihood of any part being lost.

eor

In the modified form of construction i shown in Figures 4to l0 the spring h is attached at its outer end to the expanding member Zi by springing-its end coils into an undercut recess in the member b no stem being provided in this case on said member. A helical spring a is employed for forcing the sealing member a outwardly and is connected to the spring Zi by a tubular sleeve 7 slit as shown in Figures 7 and 8 to form tongues g which are bent outwards and inwards alternately as shown. in Figures 9 to 10 and clipped over the adjacent inner end coils of the two springs a L as clearly illustrated in Figures t and 5. Sleeve f also serves to separate the coils of the two springs so that they do not interfere with one another and may be wound either in the same or opposite directions. The outer spring may also be of a different strength to the inner spring.

The detail views Figures ll. to 16 show clearly the construction of an expanding member 7) with stem 792 grooved forthe attachment of the spring b and. a sealing member c with its joint closing segments c.

in Figures l? and 18 is shown a method of forming both the springs a 7) from the same wire, the outer spring e being wound the reverse way to the inner springr to prevent the inner and outer coils engaging with each other.

This construction prevents the springs being separated and the separate coupling piece is not required as in the case where separate springs are employed. vari-f ous elements included in Figures 1l to i8 are assembled in` the manner illustrated in Figures 2l and 22.

From the foregoing description it will' be Seen that the sealing.- and expanding members a b can be moved radially outwards by springs independently of each other thus ensuring the proper expansion of the paoli-v ing and sealing'of the joint irrespective ot' Whatever variations may ole-our in2 the cylinder diameter, and regardless oil difierences in the amount of lWear on4 the tWo members..

Vith this. invention it isy alsov possible to4 close and keep closed the joints ot single cut rings althoughA thek `variations at the joint due to cylinder variationsare much greater than. in the ease oi segmental rings where the displacements, dne to cylinder Variations are dietributedy einer more than oneA joint.`

1. 'Ifile` combination with a jointed. packingf' ring, ot' independent.expanding and sealing members tor the joint of said ring, and: independent means. for forcing, said eX- pand'i'ng and sea-ling members toward' the cylinder Wall.

2. The Combination with a jointedf packing ring, of independent expanding and sealing members 'for the joint Aof said ring capable, of independent movement radially ofthe piston, and springs arranged to oper,- ate, said membersv independently off each other and move them toward the cylinder Wall'.

The combination with a packing ring for pistons, of a Wedge-shaped expanding member or Choke itting in the joint of the ring'7 a tubular sealing member slotted to receive the Wedge and to provide segments extending radially across the joint, and springs arranged to eteet the independent operationot' `the said members,

e. ik piston. ring expander and joint seal Comprising expanding and sealing members for the ring joint capable of independent movement radially of the piston, and eenneeted. e ings for operating said. members ande for preventing separation thereof 1 rior to installation.

5. A piston ring expander and joint seal comprising e ring expanding member adapted to lit in the .ring joint, a tubular sealing. member slotted at its. outer end to eeeive said expendingI member and to provide segments. to extend over thek joint ot' the ringv` and inner and outer springsr Connected to. each other and engagingl said expanding member and said sealing member respeef tively tov` move them radially of thepiston, said inner spring being connected to said expanding member.'7 whereby both members and springs are held against separation prior to installation.

ln testimony whereof he has atxed his signature.

RBERT ALLEN- 

